Negative intersect ("not intersect") is needed

feature
1

The function where suport operators "in" and "not in", but opersator "not intersect" is not supported.
In some cases, a negative operator "intersect" is needed.

6 Likes
2

Is there a way to achieve this in 2023?
where supports "intersect" but there’s no equivalent "not intersect" I’m aware of
for instance, if I want to exclude posts that have a particular tags:

{{ $pages := where .Site.RegularPages "Params.tags" "not intersect" (slice "tag1" "tag2") }}
3

A workaround with symdiff.

{{ $pages := where .Site.RegularPages "Params.tags" "intersect" (slice "tag1" "tag2") }}
{{ $pages = $pages | symdiff .Site.RegularPages }}
2 Likes
4

Just adding my +1 for this feature

5

this seems awfully inefficient. the operator is very much needed, I had that need myself a few days ago.
What would be appreciated too, is an operator returning a truth value for “do these collections intersect or not”. this would mirror the in / not in semantic perfectly.
Or better, extend in to collections indifferently, so it becomes do these elements (possibly singular) figure in that set. But I doubt we’re gonna see something so revolutionary any time soon.

6

Why? An empty slice is falsy, so…

{{ $s1 := slice "a" "b" }}
{{ $s2 := slice "b" "c" }}

{{ if intersect $s1 $s2 }}
  They intersect.
{{ else }}
  They do not intersect.
{{ end }}

An empty slice is falsy. A slice with one or more elements is truthy.

1 Like
7

ah ! I forgot ! It’s difficult to stop thinking in terms of type (to me a set is a set, not a truth value), because quite regularly the syntax comes back to bite me, complaining about said types. Sigh…
Anyway, thanks. It will come in handy.